handling overwriting existing detination

signaturizer/signaturizer.py

@@ -68,6 +68,10 @@ class Signaturizer():
                 features = len(self.modules) * 128
                 results = SignaturizerResult(len(smiles), destination,
                                              features)
+                if results.readonly:
+                    raise Exception(
+                        'Destination file already exists, ' +
+                        'delete or rename to proceed.')
                 # predict by chunk
                 all_chunks = range(0, len(smiles), chunk_size)
                 for i in tqdm(all_chunks, disable=self.verbose):
@@ -128,6 +132,7 @@ class SignaturizerResult():
                 be saved.
         """
         self.dst = destination
+        self.readonly = False
         if self.dst is None:
             # simple numpy arrays
             self.h5 = None
@@ -138,6 +143,7 @@ class SignaturizerResult():
                 print('HDF5 file %s exists, opening in read-only.' % self.dst)
                 # this avoid overwriting by mistake
                 self.h5 = h5py.File(self.dst, 'r')
+                self.readonly = True
             else:
                 # create the datasets
                 self.h5 = h5py.File(self.dst, 'w')

tests/test_signaturizer.py

@@ -87,3 +87,12 @@ class TestSignaturizer(unittest.TestCase):
         res = module.predict(self.test_smiles)
         self.assertEqual(res.signature.shape[0], 2)
         self.assertEqual(res.signature.shape[1], 128 * 25)
+
+    def test_overwrite(self):
+        module_dir = os.path.join(self.data_dir, 'B1')
+        module = Signaturizer(module_dir)
+        destination = os.path.join(self.tmp_dir, 'pred.h5')
+        module.predict(self.test_smiles, destination)
+        # repeating writing will result in an exception
+        with self.assertRaises(Exception):
+            module.predict(self.test_smiles, destination)